Spiral casing.



W. M. WHITE.

SPIRAL CASING.

APPLICATION II'LED NOV. 1, 1912,

Patented Oct. 21, 1913.

lNvEN-F'UR :ATT I: R N ELY.

WILLIAM MONROE W'HI'IE, OF MILWAUKEE, WISCONSIN.

SPIRAL CASING.

Specification of Letters Patent.

Appllcationfiled November 1, 1912. Serial No. 729,135.

Spiral Casings, of which the "following is a specification.

This invention relates to improvements in the construction of spiral casings formachinery using a fluid medium, such as hydraulic turbines, centrifugal pumps, blowers, and other similar machinery.

An object of the invention is to provide a casing for such machinery which is simple in construction and eliicientin operation. (asings for such machinery asv heretofore constructed have been formed either of'cast iron, concrete, or of plate steel. with a rectangular cross section.

. It is an object of the present invention to substitute for these former constructions a casing built up of a series of tubular sections of sheet material. Such formation of the casing ofa series of tubular sections of sheetmater-ial will permit the construction of a lighter and considerablystronger cas-.

ing at greatly reduced cost.

A clear conception of the invention as applied to a hydraulic turbine may be had by; referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the several views.

Figure l is a transverse vertical section through a sheet material hydraulic turbine spiral casing showing a Francis runner in operating position therein. 7 Fig. 2 is a top view partly in section, of a. sheet material hyc ulic turbine spiral casin The hydraulic turbine easing which is normallysupported upon a suitahle foundation 12, consists essentially of a series of tubular sections 4 having straight line genera triees extending in the direction of -flow of fluid and having one or both ends cut oft obliquely to the axis and having adjacent ends connected to form a spiral chamber. By the disclosure herein of the specificv form of the invention it is not intended that it is limited thereto but it is to be understood to include any form of section made up of straight line elements or gcneratrices which pass through a common point located some distance away up to an' infinite distance away, in which case the sections are exactly cylindrical. These sections 4 are preferably formed of shoot material such as sheet steel. although any other suitable sheet material may be used. The successive sections l, be-

Patcntcd Get. 21, 1913;.

till

ginning at the inlet end of the casing, de-

crease in diameter, thus progressively reducing the cross sectional area of the chamber formed within the casing. The inlet 16 leading into the spiral casing is formed through a circular sheet material srction 2 semicircular plate 8 and several other small casing plates, and with its opposite end to any suitable water supplying source not shown. The ends 15 of the sectionss overlap the ends 14 of the adjacent sections t, the overlapping ends 14, 15, of adjacent sections 4 being secured together by rivets 5 or any other suitable fastening means, such Welding. These ends 15 constitute portions at an angle to the remainder of the sections i, and permit of fitting perfectly to the adjacent sections to form lap joints The lap joint between the adjacent sections 4 is such that the water entering the casing chamber through the inlet 16 meets no obstruct-ions in passing'through'the casing. If the flow through the casing is to be in a direction opposite to that intended to'be had in the casing shown, as in a centrifugal pump or Whieh connects with its one edge with a fan, the ends 14 of the sections 4; would overlap the ends 15v of t he'adjacent sections 4. Th1s 1s a case where the sections might be exactly cylindrical 'in form. The inner edges of the sheet material sections at are riveted or' otherwise secured to retaining rings 1, 10, which are held in spaced relation, preferably parallel to each other, by

means of a series of tie rods 9. After the spiral easing has been assembled, the joints between the adjacent sections 4 and be tween the-sections 4 and the rings 1, 10,'ar e thoroughly calked or welded to prevent leakage. p

With the casing -.supported in position upon the foundation 12 as shown in Fig. 1,

the runner 7 having a vertical shaft 6 and the usual guide vanes 8, may be readily in sorted within the sheet material. spiral casing, in operating position. The guide vanes S are adapted to be operated by the usual operating mechanism which is well known to those skilled in the art. The. turbine discharge 11 is formed in the foundation 12 directly below the runner 7.

imr'ingthe operation of the runner i, the

Water under pressure is admitted to the spiral casing through the inlet 16 and passes from the chamber formed Within the spiral casing through the guide vanes S and runner 7, from which it is discharged into the discharge 11. It Will be noted that the reason for forming the spiral casing ofprogressively decreasing cross section is hat the single inlet 16 supplies Water to the entire periphery of the Francis turbine runner, and that the surplus amount of the water entering the casing near the inlet 16, which does not pass directly to the runner 7 passes on through the casing to a point where it is eventually freely admitted to the runner 7 of the turbine.

The casing disclosed in the drawing is applied to a Francis type of hydraulic turbine although it will be evident to those skilled in the art that a casing of this character might just as easily be applied to an impulse or any other type of turbine, centrifugal pump or similar device.

The sheet material sections 4' formed substantially cylindrical with circular cross sections and straight line elements, provide .11 very light casing adapted to Withstand very high internal pressures which subject the casing walls to high tension strains. The formation of the lap joints between success: sive sections it, also provides a casing which gradually guides the Waterto the turbine and prevents the formation of eddies or other undesiral'ile undulations in the passing flow.

It should he understood that it is not do sired to he limited to the exact details here in shown and described for obvious modifiations may occur to a person skilled in. the art.

it is claimed and. tors i-":-=.tent--- -21. A spiral casing, consisting of a series of tubular, sheet i'nateriah transverse sections said sections havirn 't aight line gen- "i the direction of flow in sail, iirl sections each having at least a portion extending to the end thereof at an angle to the remainder of said section and also having straight line generatrices to facilitate the union of said sections and said spiral casing having a conired to secure by Let-- tinuous annular inwardly directed discharge passage. v

2. A spiral casing consisting of a series of tubular, sheet material, transverse sections, said sections successively decreasing in size and having straight line generatrices extending in the direction of how in said casing and said' sections each having at least one portion extending to the end thereof at an angle to the remainder of said section and also having straight line goncratrices to Iacilitate the union of said sections and said spiral casing having a continuous annular inwardlydirected discharge passage.

3. A spiral casing consisting of a series of plate steel tubular sections, adjacent sections beingat an angle to each other in the plane of said casing, said sections having straight line cneratrices extending in the direction of dew in said casing and each having at least one edge at said angle to the remainder of said section and also having straightline generatrices to accommodate the angularity between said'sect-ions and said spiral casing having a continuous annular inwardly directed discharge passage.-

4. A spiral casing consisting of a plurality of spaced rings, and a series of sheet ma terial sections having straight line eneratrices extending in the direction of 0w in said casing and having edges secured to said rings.

i 5. A spiral casing consisting of a plurality of spaced rings, and a series of sheet material sections having straight line genera-- trices extending in the direction of flow in said casing and having overlapping ends and having edges secured to saidrings.

6, A spiral casing comprising a series of short tubtilar Sections'succcssively increasing in size'and having adjacent ends secured togetherai'id said sections being of such form that linear elements thereof extending in the direction of flow of fluid in said casing are straight.

In testimony whereof, the signature of the inventor atlixed hereto in the presence of two witnesses.

VILLIAM MONROE W'HITE.

\Vitnesses:

Council DYAS WHITE, 7. H. Tasman. 

